Expansion-joint strip



April 16, 1929. v L, M. SWOPE ET AL- 1,709,692

EXPANSION JOTNT STRIP Filed July 29, 1924 2 Sheets-Sheet l c w ve,

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April 16, 1929, L. M. SWOPE ET AL 1,709,592

EXPANSION JOINT STRIP Filed July 29, 1924 2 Sheets-Sheet 2 Patented Apr.16, 1929.

LESLIE m. sworn AND some (I. zunaur, OF.NORFOLK, vIaeInm, AssIenoas TOODENDHAL-MONKS CORPORATION, or NORFOLK, VIRGINIA, a CORPORATION orVIRGINIA.

EXPANSION -J OINT STRIP.

Application filed July 29, 1924. Serial no, 728,901.

Our invention relates to means for providing for the contraction andexpanslon-of street pavements, concrete roads'and the llke.

The object of our invention is to provide a marketable board, to be usedas an expansion oint strip in pavementconstructions, which couples thegreatest degree of expansibility and contractility with board-likerigidity and a non-adhesive'exterior.

Our invention consists in the method of construction, combination andarrangement of parts and in the completed expansion joint board as anarticle of manufacture.

In the drawings illustrative of our invention: 1

Figure 1 is a perspective view of a portion of our expansion jointboard.

Figure 2 is a similar view illustrating the sectional features.

Figure 3 is a perspective view of a modification of our expansion jointboard.

Figure 4 is a side view of a portion of our expansion joint board.

Figure 5 is a cross section view on the dotted line ma in Figure 1.

Figure 6 1s a crosssection view of a portion of our expansion jointboard when out longitudinally through the center.

Figure 7 is a similar view of the modified board in Figure 3.

Figure 8 is a sectional perspective v ew of a. concrete road with ourinvention in use.

The expansion joint board constructed ac cording to our inventioncomprises a body of relatively thick cross-section of asphalt orsuitable bituminous material of board-like formation, perforatedtransversely with a series of holes reinforced on each side by alongitudinal strip of fibre board of sufficient with to cover the holes,and having relatively thin side-surfacing sheets of asbestos.

We prefer to construct theboard asshow'n in Figures 1, 2, 4, 5 and 6, byfirst laying a sheet of asbestos 3 in size equal to the side of theproposed joint on the bottom of a mould shaped to fit, and upon this.longitudmally through the center of the asbestos a strip of fibre board2 four inches wide the full length of the mould. Then on top of thefibre board along the center we place oval disks two inches in verticaldiameter and six inches apart and with the thickness of the desiredexpansion board. Asphalt 1 is then poured- 'into the mould and aroundthe disks to the thickness desird and allowed to cool, when the disksare removed, leaving a two inch hole 4.- every six inches apart. Overthe series of holes thus made, a second strip of fibre board 2 similarto the first is laid and on the' top of the fibre board is placed asecond sheet of asbestos 3 in size equal to thefirst. Pressure isapplied by rollers or weights to obtain cohesion of the several parts,thus making a built-up expansion joint board of two sheets of asbestos,two strips of fibre board and a filling of asphalt with a line of twoinch holes transversely through the center.

' Our invention is ca able of some modification and variation from thestructure as above described, as for instance, other reinforcingmaterials may be used in conjunction with the vacuum spaces instead ofasbestos sheeting, or the asbestos side-sheeting may be saturated withasphaltio compound to Waterproof the same, thus making the boardslessnon-adhesive but retaining the other advantages of plain asbestossheeting, or again,

the holes may vary in number and size or may be eliminated entirelyalong with the'supporting fibre board, as in Figures 3 and 7 thusobtaining an asphalt asbestos board of less 'contractility but ofgreater economy in manufacture. I

Our asbestos, perforated, asphalt board constitutes a practicalimprovement and novelty over other expansion joints now in use. It is anexceedingly old expedient both to preform elastic joints for pavementsand to use asphalt or bituminous material in such joints. A plainasphalt preformed jbint, however, is fundamentally defective, because incold weather, it is brittle and easily broken, while in hot weather itlacks rigidit and becomes sticky, making handling di fli cult andstorage or shipping impossible, since the planks, when piled up, willgum together. This very early suggested the idea of reinforcing suchjoint strips either internally or externally and of covering'the sidesthereof with non-adhesive material, which ideas are now common propertyby expiration of patent, and therefore we do not claim such combinationsbroadly. We are also aware that, prior to our invention, asphalt jointstrips have been made with external reinforcements and covering,consisting of paper, elastic felt and saturated felt etc., and thatLetters Patent have been granted limited to the specific the use ofasbestos sheeting in combination with paving joint strips constitutes adistinct novelty.

In the first place, asbestos is a mineral.

whereas canvas, paper, felt and the like, as heretofore used in jointstrips, are all made from vegetable and animal matter. It will lastindefinitely because it is made of rock,

There-is nothing in it to rot or dry out. In

fact, one of the most valuable properties of this mineral, is vitsdurability against such "forces of disintegration as heat, cold, fireand moisture. This "rock is ideally suited to paving construction,necessarily more so than vegetable and animal felts etc. Beginning withthe manufacture of the joint strip, the molten asphalt partiallypermeates the asbestos sheeting and the'saturated area be- 7 comes amineral compound. Then when the board is set and wet cement is pouredalongside it, the moisture of the cement loosens the fibres of theremaining asbestos, and the wet cement fills in between the fibres, sothat the asbestos fibres becomes a part and parcel of the cementcompound. When the cement dries and hardens, there is left a solidmineral joint, less likely to leave a crevice between the pavement andthe joint filler for water and other damaging elements to enter. In-

this closed joint there is no foreignmatter to rot or decay under theforce of the elements, viz, heat, cold, light and water.

In the second place, asbestos sheeting makes a better finish to thejoint strip than eitherfelt, paper or cloth, while possessing reinforcinqualities equal or superior to them,

' thus 0 ering distinct advantages in handling,

storing and shipping. If paper or cloth is used, the molten asphaltpoured in the mould or otherwise used in making the joint, will permeatethe pores of the paper or cloth and oozing outward, will keep the jointstrip more or less sticky in hot weather. Thin canvas likewise; andthick canvas is of prohibitive cost. Felt, if saturated, as the feltcommonly used, presents a sticky and gummy surface on the side of thejoint strip in hot weather;

and ifnot saturated, will deteriorate and decay quickly in the joint.Molten asphalt and similar bituminousm'aterials do not saturate "throughasbestos sheeting, the fibres of-which are interlocking, and thereforethe joint strip with asbestos sides is entirelynon-adhesive filler,preserving the filler. from fluidity and" retaining a greater board-likerigidity inthe joint-strip. This,vof course, makes our joint 1 stripssuperiorto the pliable and gummy rag felt, cloth and paper reinforcedstripsin the shipping and storing.

matters of handling, When set up in the joint, moreover, this charactertends to a certain extent to retard oozing of the filier out of thejoint in hot weather, with its accompanying disadvantages.

Likewise, our use of perforations or a series of holes represents adistinct improvement over otherpreformed joints, all of which are ofsolid construction. When the latter are installed, they have no spacesfor expansion and. in hot weather,,the asphalt filler has a tendency toooze upward upon the pavement, because this is the only outlet forexpansion. As explained-above, this is undesirable. Our inventionprovides chambers within the joint itself, into which the asphalt fillerwill tend to expand, thus presenting a joint of superior contractilityand minimizing the expansion upward upon the pavement. The central fibreboard strips 2 used to cover the holes, as in Figure 2, are necessary toprevent the cement used in adjacent paving from filling the chambers 4.

WVe claim:

1. As an articleof manufacture, an expansion oint strip comprising abody of relatively thick cross-section of'asphalt or suit-- ly thinside-surfacing sheets of asbestos.

2. As an article of manufacture, an expansion joint board comprising abody of asiphalt or-suitable bituminous material, perforated with aseries of holes co vered and reinforced by strips of suitable sidesurfacing material. Y LESLIE M. SWOPE. JOHN C. ZULAUF.

